harpocrates

Harpocrates - An Efficient Encryption for Data-at-rest

Overview

harpocrates is an implementation of an efficient algorithm for encrypting data-at-rest. Each message block ( 16 -bytes ) can be independently encrypted/ decrypted, given that (inverse) look up table ( read LUT ) has already been generated. State size of this lightweight cipher is only 128 -bit & it's powered by substitution convolution network ( read SCN ). Only substitution, bit shifting, bit rotation & XOR are used as primitive operations.

Note, (inv) LUT generation is one-time operation.

Here I'm keeping a zero-dependency, easy-to-use C++ header-only library ( using C++20 features ), implementing Harpocrates specification, as described here. This implementation can be compiled targeting both CPUs, GPUs ( using SYCL ).

Prerequisites

• Ensure you've C++ compiler such as g++/ clang++, along with C++20 standard library

I'm using

$ g++ --version
g++ (Ubuntu 11.2.0-19ubuntu1) 11.2.0

• You'll also need to have standard system development utilities such as make/ cmake

I'm using

$ make --version
GNU Make 4.3

$ cmake --version
cmake version 3.22.1

• For benchmarking Harpocrates implementation on CPU, you need to have google-benchmark library globally installed; see this

Testing

For testing functional correctness of Harpocrates cipher implementation, issue following command, which runs two kinds of tests

• Asserting results against Known Answer Tests ( read KATs ) supplied with Harpocrates specification [ Correctness & Conformance ]
• With randomly generated message blocks, attempt to execute encrypt -> decrypt cycle [ Correctness ]

make

Benchmarking

For benchmarking Harpocrates cipher implementation, using single message block ( 16 -bytes ), on CPU, issue

make benchmark

ARM Cortex-A72

2022-05-12T20:24:55+05:30
Running ./bench/a.out
Run on (4 X 1800 MHz CPU s)
Load Average: 3.25, 0.98, 0.57
------------------------------------------------------------------------------
Benchmark                    Time             CPU   Iterations UserCounters...
------------------------------------------------------------------------------
harpocrates_encrypt       2349 ns         2349 ns       296555 bytes_per_second=6.49583M/s
harpocrates_decrypt       2317 ns         2317 ns       302110 bytes_per_second=6.58582M/s

Usage

harpocrates being C++ header-only library, using it's as easy as including ./include/harpocrates.hpp in your program, while asking your compiler to include ./include in its INCLUDE_PATH ( using -I flag ).

• Ideally you'd want to use harpocrates_utils:: namespace for generating (inv)LUT, which is one-time process ( in pre-compute phase )
• After that you'll only need harpocrates:: namespace, which implements encrypt/ decrypt routines
• You may also want to see harpocrates_common:: namespace, which defines some constants

I've kept harpocrates API usage example here.